| bullheaded(adjective, tough, firm, determined, unreasonable) |
| decisive(adjective, determined, serious, resolute, persistent) |
| laborious(adjective, hardworking) |
| perseverant |
| thorough(adjective, resolute) |
| true(adjective, strong, tough, flat, firm) |
| unbending(adjective, strong, tough, flat, firm) |
| unfailing(adjective, set, strong, firm, energetic) |
| unwearied(adjective, strong, firm, energetic, determined) |
| bulldogged(adjective, tenacious) |
| careful(adjective, thorough, meticulous, painstaking) |
| committed(adjective, resolute, persistent, dedicated, unwavering) |
| courageous(adjective, firm, determined, resolute, brave) |
| hard(adjective, resolution, tenacious) |
| hard-working(adjective, thorough, meticulous, painstaking) |
| immovable(adjective, determined, steady, resolute, persistent) |
| intent(adjective, strong, flat, certain, determined) |
| mulish(adjective, tough, firm, determined, unreasonable) |
| painstaking(adjective, thorough, meticulous) |
| pigheaded(adjective, tough, firm, determined, unreasonable) |